Calibration of a reconfigurable array of omnidirectional cameras using a moving person

Reconfigurable arrays of omnidirectional cameras are useful for applications where multiple cameras working together are to be deployed at a short notice. This paper addresses the important issue of calibration of such arrays in terms of the relative camera positions and orientations. The location of a one-dimensional object moving parallel to itself, such as a moving person is used to establish correspondences between multiple cameras. In such case, the non-linear 3-D problem of calibration can be approximated by a 2-D problem in plan view. This enables an initial solution using factorization method. A non-linear optimization stage is then used to account for the approximations, as well as to minimize the geometric error between the observed and projected omni pixel coordinates. Experimental results with simulated and real data illustrate the effectiveness of the method.